Some of what you are referring to is deep rooted issues in the game design. While there are some benefits to mob scaling for example it is problematic for many builds and players.
This upcoming Mod does addresses that specific issue by using Static Leveling where creatures have set levels, stats, and exp rewards.
However, also note everything is being changed in this mod and if you are looking for the original game experience this will be quite different.
This Mod also addresses other issues you mention like the scaling/power issues. Nearly all multipliers are being removed as they most often just lead to balancing issues.
It’s very typical in Grim Dawn & Path of Exile to have a build where you gain 100% of your HP from hitting creatures every second.
Example Infinity Fix: The Soldiers Will skill increases HP regen and gives a percent boost of HP back. The percent boost was removed, the reuse timer adjusted, and you gain a healthy set amount of HP back (determined by the skill level).
Constitution was removed as well as percentage based health potions. These are done to have much better control over balance and address many of the issues you mention.